For use with the newly added openat and friends API, add O_PATH file
descriptors that are not usable for doing actual I/O, but only for use
as dirfd.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
v1 -> v2:
- rename allow_pathonly to o_path_ok (Sascha)
---
fs/fs.c | 58 +++++++++++++++++++++++++++++--------------------
include/fcntl.h | 1 +
2 files changed, 35 insertions(+), 24 deletions(-)
diff --git a/fs/fs.c b/fs/fs.c
index 6b71440318af..cda1f39519fe 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -325,12 +325,16 @@ static void put_file(FILE *f)
dput(f->dentry);
}
-static FILE *fd_to_file(int fd)
+static FILE *fd_to_file(int fd, bool o_path_ok)
{
if (fd < 0 || fd >= MAX_FILES || !files[fd].in_use) {
errno = EBADF;
return ERR_PTR(-errno);
}
+ if (!o_path_ok && (files[fd].flags & O_PATH)) {
+ errno = EINVAL;
+ return ERR_PTR(-errno);
+ }
return &files[fd];
}
@@ -359,7 +363,7 @@ static int fsdev_truncate(struct device *dev, FILE *f, loff_t length)
int ftruncate(int fd, loff_t length)
{
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -381,7 +385,7 @@ int ftruncate(int fd, loff_t length)
int ioctl(int fd, int request, void *buf)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -426,7 +430,7 @@ static ssize_t __read(FILE *f, void *buf, size_t count)
ssize_t pread(int fd, void *buf, size_t count, loff_t offset)
{
loff_t pos;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -443,7 +447,7 @@ EXPORT_SYMBOL(pread);
ssize_t read(int fd, void *buf, size_t count)
{
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -495,7 +499,7 @@ static ssize_t __write(FILE *f, const void *buf, size_t count)
ssize_t pwrite(int fd, const void *buf, size_t count, loff_t offset)
{
loff_t pos;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -512,7 +516,7 @@ EXPORT_SYMBOL(pwrite);
ssize_t write(int fd, const void *buf, size_t count)
{
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -529,7 +533,7 @@ EXPORT_SYMBOL(write);
int flush(int fd)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -547,7 +551,7 @@ int flush(int fd)
loff_t lseek(int fd, loff_t offset, int whence)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
loff_t pos;
int ret;
@@ -600,7 +604,7 @@ EXPORT_SYMBOL(lseek);
int erase(int fd, loff_t count, loff_t offset)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -629,7 +633,7 @@ EXPORT_SYMBOL(erase);
int protect(int fd, size_t count, loff_t offset, int prot)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -656,7 +660,7 @@ EXPORT_SYMBOL(protect);
int discard_range(int fd, loff_t count, loff_t offset)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
int ret;
if (IS_ERR(f))
@@ -697,7 +701,7 @@ int protect_file(const char *file, int prot)
void *memmap(int fd, int flags)
{
struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, false);
void *retp = MAP_FAILED;
int ret;
@@ -721,20 +725,23 @@ EXPORT_SYMBOL(memmap);
int close(int fd)
{
- struct fs_driver *fsdrv;
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, true);
int ret = 0;
if (IS_ERR(f))
return -errno;
- fsdrv = f->fsdev->driver;
+ if (!(f->flags & O_PATH)) {
+ struct fs_driver *fsdrv;
- if (fsdrv != ramfs_driver)
- assert_command_context();
+ fsdrv = f->fsdev->driver;
- if (fsdrv->close)
- ret = fsdrv->close(&f->fsdev->dev, f);
+ if (fsdrv != ramfs_driver)
+ assert_command_context();
+
+ if (fsdrv->close)
+ ret = fsdrv->close(&f->fsdev->dev, f);
+ }
put_file(f);
@@ -1056,7 +1063,7 @@ static void stat_inode(struct inode *inode, struct stat *s)
int fstat(int fd, struct stat *s)
{
- FILE *f = fd_to_file(fd);
+ FILE *f = fd_to_file(fd, true);
if (IS_ERR(f))
return -errno;
@@ -2173,7 +2180,7 @@ static const char *path_init(int dirfd, struct nameidata *nd, unsigned flags)
* whether paths are absolute with openat(-1, path, O_PATH)
*/
if (dirfd != AT_FDCWD)
- f = fd_to_file(dirfd);
+ f = fd_to_file(dirfd, true);
if (*s == '/') {
get_root(&nd->path);
@@ -2590,7 +2597,7 @@ int openat(int dirfd, const char *pathname, int flags)
error = -ENOENT;
goto out1;
}
- } else {
+ } else if (!(flags & O_PATH)) {
if (d_is_dir(dentry) && !dentry_is_tftp(dentry)) {
error = -EISDIR;
goto out1;
@@ -2617,6 +2624,9 @@ int openat(int dirfd, const char *pathname, int flags)
f->fsdev = fsdev;
+ if (flags & O_PATH)
+ return f->no;
+
if (fsdrv->open) {
char *pathname = dpath(dentry, fsdev->vfsmount.mnt_root);
@@ -2653,7 +2663,7 @@ static const char *fd_getpath(int fd)
if (fd < 0)
return ERR_PTR(errno_set(fd));
- f = fd_to_file(fd);
+ f = fd_to_file(fd, true);
if (IS_ERR(f))
return ERR_CAST(f);
diff --git a/include/fcntl.h b/include/fcntl.h
index a6ed50b92eaf..a3f5d96cd0ac 100644
--- a/include/fcntl.h
+++ b/include/fcntl.h
@@ -23,6 +23,7 @@
#define O_APPEND 00002000
#define O_DIRECTORY 00200000 /* must be a directory */
#define O_NOFOLLOW 00400000 /* don't follow links */
+#define O_PATH 02000000 /* open as path */
#define __O_TMPFILE 020000000
#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
--
2.39.2
